Although reduced scale multirotor aircraft (sometimes called multi-copters) are not new, they have been reduced scale models not intended for the rigors or requirements of carrying human passengers, and are mostly used either as toys, or for limited-duration surveillance or aerial photography missions with motion being controlled by radio-control remotes. Most if not all are battery powered. For example, US Patent Application 20120083945 relates specifically to a reduced scale multi-copier, but does not address the safety, structural, or redundancy features necessary for an FAA-certified passenger-carrying implementation, nor any of the systems required to implement a practical, passenger-carrying vehicle with fault-tolerance and state-variable analysis, nor any way of generating its own power from fuel carried on-board. The dynamics and integrity requirements of providing a full scale aircraft capable of safely and reliably carrying human passengers and operating within US and foreign airspace are significantly different that those of previous reduced scale models.
Therefore, a full scale multi-copter implementation that finds applications for commuting, for recreation, for inter-city transportation, for industrial, for delivery, or for security and surveillance applications among others with human passengers on board, based on state-of-the-art electric motor and electronics and computer technology with high reliability, safety, simplicity, and redundant control features, with on-board capability to generate its own electrical power (as opposed to simply consuming energy previously stored in electro-chemical batteries), coupled with advanced avionics and flight control techniques is described.
A large volume of personal travel today occurs by air. For destinations of more than 500 miles, it has historically been the fastest travel mode and, in terms of injuries per passenger mile, the safest. However, only about 200 hub and spoke airports exist within the US, placing much of the population more than 30 minutes away from an airport. Yet there are over 5,300 small control-towered regional airports, and over 19,000 small airfields with limited or no control towers throughout the US, placing more than 97% of the population within 15 to 30 minutes of an airfield. As many have noted before, this is a vastly under-utilized capability.
In the 21st Century, the opportunity is available to apply advanced technologies of the evolving National Airspace System (NAS) to enable more-distributed, decentralized travel in the three-dimensional airspace, leaving behind many of the constraints of the existing hub-and-spoke airport system, and the congestion of the 2-dimensional interstate and commuter highway systems.
Many large cities such as Boston, Houston, Los Angeles and other major metropolitan areas are virtually gridlocked by commuter traffic, with major arteries already at or above capacity, and with housing and existing businesses posing serious obstacles to widening or further construction. NASA, in its ‘Life After Airliners’ series of presentations (see Life After Airliners VI, EAA AirVenture 2003, Oshkosh, Wis. Aug. 3, 2003, and Life After Airliners VII, EAA AirVenture 2004, Oshkosh, Wis. Jul. 30, 2004) and NASA's Dr. Bruce Holmes (see Small Aircraft Transportation System—A Vision for 21st Century Transportation Alternatives, Dr. Bruce J. Holmes, NASA Langley Research Center. 2002) make the case for a future of aviation that is based on the hierarchical integration of Personal Air Vehicles (PAV), operating in an on-demand, disaggregated, distributed, point-to-point and scalable manner, to provide short haul air mobility. Such a system would rely heavily on the 21st century integrated airspace, automation and technology rather than today's centralized, aggregated, hub-and-spoke system. The first, or lowest tier in this hierarchical vision are small, personal Air Mobility Vehicles or aircraft, allowing people to move efficiently and simply from point-to-any-point, without being restricted by ground transportation congestion or the availability of high-capability airports. Key requirements include reduced or eliminated noise impacts to communities, vehicle automation, operations in non-radar-equipped airspace and at non-towered facilities, green technologies for propulsion, increased safety and reliability, and en-route procedures and systems for integrated operation within the National Airspace System (NAS) or foreign equivalents. Ultimate goals cited by NASA include an automated self-operated aircraft, and a non-hydrocarbon-powered aircraft for intra-urban transportation. NASA predicts that, in time, up to 45% of all future miles traveled will be in Personal Air Vehicles.
This invention addresses part of the core vision established by NASA, and documents the concept and design of an clean-fueled, electric multirotor vehicle, referred to herein as a multirotor aircraft, or an e-copter, or an Air Mobility Vehicle, as one part of the On-Demand, Widely Distributed Point-to-Any Point 21st Century Air Mobility system. Operation of the vehicle is simple and attractive to many operators when operating under Visual Flight Rules (VFR) in Class E or Class G airspace as identified by the Federal Aviation Administration, thus in most commuter situations not requiring any radio interactions with Air Traffic Control towers.